Reverting a commit before pushing#
When we have created a commit locally but have not published it to the remote yet, we can use git reset to undo the commit and, if we wish, discard the changes.
Although there are several options for git reset the most used are:
--soft: Does not touch the index file or the working tree at all (but resets the head to, just like all modes do). This leaves all your changed files “Changes to be committed”, as git status would put it. --hard: Resets the index and working tree. Any changes to tracked files in the working tree sinceare discarded. Any untracked files or directories in the way of writing any tracked files are simply deleted. Git reset documentation {: style=“text-align: right;”}
Here there is an example about using git reset. We start by changing a file and creating a commit with the change.
bash-3.2$ cat README.md
# Index
1
bash-3.2$
bash-3.2$ cat README.md
# Index
1
2
bash-3.2$
bash-3.2$ git add README.md
bash-3.2$
bash-3.2$ git commit -m "Add number 2 in README.md"
[main 3734fd5] Add number 2 in README.md
1 file changed, 1 insertion(+)
git status shows there is one commit pending to be published.
bash-3.2$ git status
On branch main
Your branch is ahead of 'origin/main' by 1 commit.
(use "git push" to publish your local commits)
nothing to commit, working tree clean
Using git reflog to see the history.
3734fd5 (HEAD -> main) HEAD@{0}: commit: Add number 2 in README.md
866bfa8 (origin/main) HEAD@{1}: revert: Revert "Merge branch 'feature-1'"
e2f6d08 HEAD@{2}: merge feature-1: Merge made by the 'ort' strategy.
23644da HEAD@{3}: checkout: moving from feature-1 to main
Now we can use git reset --soft <COMMIT_ID> to undo the commit but keep the changes.
bash-3.2$ git reset --soft 866bfa8
bash-3.2$
bash-3.2$ git status
On branch main
Your branch is up to date with 'origin/main'.
Changes to be committed:
(use "git restore --staged <file>..." to unstage)
modified: README.md
git log after using git reset
commit 866bfa8a952d11240707ebfc87f3266034d42443 (HEAD -> main, origin/main)
Author: Julian Nonino <learn.software.eng+jnonino@gmail.com>
Date: Wed Jan 18 20:06:40 2023 -0300
Revert "Merge branch 'feature-1'"
This reverts commit e2f6d08d3b38a02a1c026cfb879f3131536757ac, reversing
changes made to 23644dab9fc5828ecdd358c6d3acb4196ed23546.
We create a new commit so we can test the git reset --hard command.
bash-3.2$ git status
On branch main
Your branch is up to date with 'origin/main'.
Changes to be committed:
(use "git restore --staged <file>..." to unstage)
modified: README.md
bash-3.2$ git commit -m "Add number 2 in README.md - NEW COMMIT"
[main 2e7193d] Add number 2 in README.md - NEW COMMIT
1 file changed, 1 insertion(+)
git log now shows the new commit.
commit 2e7193db650b9ba0762fe73525df599a08f8577d (HEAD -> main)
Author: Julian Nonino <learn.software.eng+jnonino@gmail.com>
Date: Thu Jan 19 08:32:57 2023 -0300
Add number 2 in README.md - NEW COMMIT
commit 866bfa8a952d11240707ebfc87f3266034d42443 (origin/main)
Author: Julian Nonino <learn.software.eng+jnonino@gmail.com>
Date: Wed Jan 18 20:06:40 2023 -0300
Revert "Merge branch 'feature-1'"
This reverts commit e2f6d08d3b38a02a1c026cfb879f3131536757ac, reversing
changes made to 23644dab9fc5828ecdd358c6d3acb4196ed23546.
Now we can use git reset --hard <COMMIT_ID> to undo the commit and discard all the changes.
bash-3.2$ git reset --hard 866bfa8
HEAD is now at 866bfa8 Revert "Merge branch 'feature-1'"
bash-3.2$
bash-3.2$ git status
On branch main
Your branch is up to date with 'origin/main'.
nothing to commit, working tree clean
git log remains as it nothing had happened.
commit 866bfa8a952d11240707ebfc87f3266034d42443 (HEAD -> main, origin/main)
Author: Julian Nonino <learn.software.eng+jnonino@gmail.com>
Date: Wed Jan 18 20:06:40 2023 -0300
Revert "Merge branch 'feature-1'"
This reverts commit e2f6d08d3b38a02a1c026cfb879f3131536757ac, reversing
changes made to 23644dab9fc5828ecdd358c6d3acb4196ed23546.
Reverting a commit after it was pushed#
When we realized that the last commit was a mistake but we already published it, the command to use is git revert <COMMIT_HASH>.
- First we need to locate the ID of the commit we want to revert, it can be done with
git logorgit reflogcommands. - Then, run the
git revert <COMMIT_HASH>command using the ID obtained in the previous step. Use the options-eor--editto edit the commit message if we like. - Push our changes so the revert is available for everyone in our group.
Reverting multiple commits#
If we need to revert multiple commits we can revert them one by one using the --no-commit option in order to create a single revert commit at the end.
Imagine the history is like the following and we need to go back to COMMIT-3.
COMMIT-1 -> COMMIT-2 -> COMMIT-3 -> COMMIT-4 -> COMMIT-5 -> COMMIT-6 -> HEAD
This sequence of commands will get our files to the version of COMMIT-3:
bash-3.2$ git revert --no-commit COMMIT-6
bash-3.2$ git revert --no-commit COMMIT-5
bash-3.2$ git revert --no-commit COMMIT-4
bash-3.2$ git commit -m "Revert to version in COMMIT-3"
bash-3.2$ git push
Reverting a merge commit#
-m parent-number, –mainline parent-number
Usually you cannot revert a merge because you do not know which side of the merge should be considered the mainline. This option specifies the parent number (starting from 1) of the mainline and allows revert to reverse the change relative to the specified parent.
Git revert documentation {: style=“text-align: right;”}
When we need to revert a merge commit git revert command needs to be run with the -m or --mainline option to indicate the parent number because a merge commit has more than one parent and Git does not know which parent was target branch and which was the branch with the changes that should be reverted.
Here there is an example showing how to revert a merge commit.
Create the first commit in main branch.
bash-3.2$ cat README.md
# Index
1
bash-3.2$
bash-3.2$ git commit -m "Add number 1 in README.md - main branch"
[main (root-commit) 23644da] Add number 1 in README.md - main branch
1 file changed, 3 insertions(+)
create mode 100644 README.md
bash-3.2$
bash-3.2$ git push -u origin main
Enumerating objects: 3, done.
Counting objects: 100% (3/3), done.
Writing objects: 100% (3/3), 254 bytes | 254.00 KiB/s, done.
Total 3 (delta 0), reused 0 (delta 0), pack-reused 0
To github.com:jnonino/test-repo.git
* [new branch] main -> main
branch 'main' set up to track 'origin/main'.
bash-3.2$
The state of the README.md file in main branch.
bash-3.2$git status
On branch main
Your branch is up to date with 'origin/main'.
nothing to commit, working tree clean
bash-3.2$
bash-3.2$ cat README.md
# Index
1
Branch feature-1 created and added one commit.
bash-3.2$ git checkout -b feature-1
Switched to a new branch 'feature-1'
bash-3.2$
bash-3.2$ cat README.md
# Index
1
2
bash-3.2$
bash-3.2$ git add README.md
bash-3.2$
bash-3.2$ git commit -m "Add number 2 in README.md - feature-1 branch"
[feature-1 83ea1a3] Add number 2 in README.md - feature-1 branch
1 file changed, 1 insertion(+)
bash-3.2$
bash-3.2$ git push --set-upstream origin feature-1
Enumerating objects: 5, done.
Counting objects: 100% (5/5), done.
Writing objects: 100% (3/3), 292 bytes | 292.00 KiB/s, done.
Total 3 (delta 0), reused 0 (delta 0), pack-reused 0
remote:
remote: Create a pull request for 'feature-1' on GitHub by visiting:
remote: https://github.com/jnonino/test-repo/pull/new/feature-1
remote:
To github.com:jnonino/test-repo.git
* [new branch] feature-1 -> feature-1
branch 'feature-1' set up to track 'origin/feature-1'.
bash-3.2$
The state of README.md in the feature-1 branch.
bash-3.2$ git status
On branch feature-1
Your branch is up to date with 'origin/feature-1'.
nothing to commit, working tree clean
bash-3.2$
bash-3.2$ cat README.md
# Index
1
2
Merge the feature-1 branch into the main branch.
bash-3.2$ git checkout main
Switched to branch 'main'
Your branch is up to date with 'origin/main'.
bash-3.2$
bash-3.2$ git merge --no-ff feature-1
Merge made by the 'ort' strategy.
README.md | 1 +
1 file changed, 1 insertion(+)
bash-3.2$
bash-3.2$ git push
Enumerating objects: 1, done.
Counting objects: 100% (1/1), done.
Writing objects: 100% (1/1), 233 bytes | 233.00 KiB/s, done.
Total 1 (delta 0), reused 0 (delta 0), pack-reused 0
To github.com:jnonino/test-repo.git
23644da..e2f6d08 main -> main
bash-3.2$
Current state of README.md in main branch.
bash-3.2$ git status
On branch main
Your branch is up to date with 'origin/main'.
nothing to commit, working tree clean
bash-3.2$
bash-3.2$ cat README.md
# Index
1
2
git log after merging feature-1 into main branch.
commit e2f6d08d3b38a02a1c026cfb879f3131536757ac (HEAD -> main, origin/main)
Merge: 23644da 83ea1a3
Author: Julian Nonino <learn.software.eng+jnonino@gmail.com>
Date: Wed Jan 18 19:58:19 2023 -0300
Merge branch 'feature-1'
commit 83ea1a347e0e87b19a611997219089b5b9247d1f (origin/feature-1, feature-1)
Author: Julian Nonino <learn.software.eng+jnonino@gmail.com>
Date: Wed Jan 18 19:53:38 2023 -0300
Add number 2 in README.md - feature-1 branch
commit 23644dab9fc5828ecdd358c6d3acb4196ed23546
Author: Julian Nonino <learn.software.eng+jnonino@gmail.com>
Date: Wed Jan 18 19:48:37 2023 -0300
Add number 1 in README.md - main branch
To revert the merge commit, as it was stated above we need to pay attention to the merge field.
Merge: 23644da 83ea1a3
Running git revert e2f6d08 -m 1 will reinstate the tree as it was in 23644da, and git revert e2f6d08 -m 2 will set the tree as it was in 83ea1a3.
In this example we would like to leave the main branch as it was before the merge commit. For doing that, we need to run git revert e2f6d08 -m 1.
bash-3.2$ git revert e2f6d08 -m 1
[main 866bfa8] Revert "Merge branch 'feature-1'"
1 file changed, 1 deletion(-)
bash-3.2$
bash-3.2$ git status
On branch main
Your branch is ahead of 'origin/main' by 1 commit.
(use "git push" to publish your local commits)
nothing to commit, working tree clean
bash-3.2$
bash-3.2$ git push
Enumerating objects: 5, done.
Counting objects: 100% (5/5), done.
Writing objects: 100% (3/3), 344 bytes | 344.00 KiB/s, done.
Total 3 (delta 0), reused 0 (delta 0), pack-reused 0
To github.com:jnonino/test-repo.git
e2f6d08..866bfa8 main -> main
git log after reverting the merge commit.
commit 866bfa8a952d11240707ebfc87f3266034d42443 (HEAD -> main, origin/main)
Author: Julian Nonino <learn.software.eng+jnonino@gmail.com>
Date: Wed Jan 18 20:06:40 2023 -0300
Revert "Merge branch 'feature-1'"
This reverts commit e2f6d08d3b38a02a1c026cfb879f3131536757ac, reversing
changes made to 23644dab9fc5828ecdd358c6d3acb4196ed23546.
commit e2f6d08d3b38a02a1c026cfb879f3131536757ac
Merge: 23644da 83ea1a3
Author: Julian Nonino <learn.software.eng+jnonino@gmail.com>
Date: Wed Jan 18 19:58:19 2023 -0300
Merge branch 'feature-1'
commit 83ea1a347e0e87b19a611997219089b5b9247d1f (origin/feature-1, feature-1)
Author: Julian Nonino <learn.software.eng+jnonino@gmail.com>
Date: Wed Jan 18 19:53:38 2023 -0300
Add number 2 in README.md - feature-1 branch
commit 23644dab9fc5828ecdd358c6d3acb4196ed23546
Author: Julian Nonino <learn.software.eng+jnonino@gmail.com>
Date: Wed Jan 18 19:48:37 2023 -0300
Add number 1 in README.md - main branch
Current state of README.md in main branch.
bash-3.2$ git status
On branch main
Your branch is up to date with 'origin/main'.
nothing to commit, working tree clean
bash-3.2$
bash-3.2$ cat README.md
# Index
1